Comparison of signalling mechanisms involved in rat mesenteric microvessel contraction by noradrenaline and sphingosylphosphorylcholine

1. We have compared the signalling mechanisms involved in the pertussis toxin-sensitive and -insensitive contraction of rat isolated mesenteric microvessels elicited by sphingosylphosphorylcholine (SPC) and noradrenaline (NA), respectively. 2. The phospholipase D inhibitor butan-1-ol (0.3%), the store-operated Ca(2+) channel inhibitor SK>F 96,365 (10 μM), the tyrosine kinase inhibitor genistein (10 μM), and the src inhibitor PP2 (10 μM) as well as the negative controls (0.3% butan-2-ol and 10 μM diadzein and PP3) had only little effect against either agonist. 3. Inhibitors of phosphatidylinositol-3-kinase (wortmannin and LY 294,002, 10 μM each) or of mitogen-activated protein kinase kinase (PD 98,059 and U 126, 10 μM each) did not consistently attenuate NA- and SPC-induced contraction as compared to their vehicles or negative controls (LY 303,511 or U 124). 4. The phospholipase C inhibitor U 73,122 (10 μM) markedly inhibited the SPC- and NA-induced contraction (70% and 88% inhibition of the response to the highest NA and SPC concentration, respectively), whereas its negative control U 73,343 (10 μM) caused only less than 30% inhibition. 5. The rho-kinase inhibitors Y 27,632 (10 μM) and fasudil (30 μM) caused a rightward-shift of the NA concentration-response curve by 0.7–0.8 log units and reduced the response to 10 μM SPC by 88% and 83%, respectively. 6. These data suggest that SPC and NA, while acting on different receptors coupling to different G-protein classes, elicit contraction of rat mesenteric microvessels by similar signalling pathways including phospholipase C and rho-kinase

Multiscale Morphology of Organic Semiconductor Thin Films Controls the Adhesion and Viability of Human Neural Cells

We investigate how multiscale morphology of functional thin films affects the in vitro behavior of human neural astrocytoma 1321N1 cells. Pentacene thin film morphology is precisely controlled by means of the film thickness, Θ (here expressed in monolayers (ML)). Fluorescence and atomic force microscopy allow us to correlate the shape, adhesion, and proliferation of cells to the morphological properties of pentacene films controlled by saturated roughness, σ, correlation length, ξ, and fractal dimension, df. At early incubation times, cell adhesion exhibits a transition from higher to lower values at Θ ≈ 10 ML. This is explained using a model of conformal adhesion of the cell membrane onto the growing pentacene islands. From the model fitting of the data, we show that the cell explores the surface with a deformation of the membrane whose minimum curvature radius is 90 (± 45) nm. The transition in the adhesion at ∼10 ML arises from the saturation of ξ accompanied by the monotonic increase of σ, which leads to a progressive decrease of the pentacene local radius of curvature and hence to the surface area accessible to the cell. Cell proliferation is also enhanced for Θ < 10 ML, and the optimum morphology parameter ranges for cell deployment and growth are σ ≤ 6 nm, ξ > 500 nm, and df > 2.45. The characteristic time of cell proliferation is τ ≈ 10 ± 2 h